Research On High Precision Process Calibrator

The process calibrator is a calibration tools used in the industry process field to ensure the safe and reliable operation during the production process, which is mainly used to demarcate and detect the transmitter, sensor and other instruments used in the industry control. In this thesis a high precision voltage/current calibrator is designed. The paper introduced the whole scheme of the system and the realization of hardware and software, and accomplished the demarcation of the system's performance index. In the end it presents a prospect based on all the works to better the system.All the researches in the paper include four aspects as follows:(1) Designing of the precise signal conditioning circuit. The paper presented the design of conditioning circuit for analog signals based on the design theory of precision circuit, discussed the sources of the noise and measures for anti-jamming and established the power system.(2) Research on high precision data converting circuit. Much work was done in the paper to analyze the sigma-delta ADC's principle, create the A/D converting and control circuits based on a kind of systematic-level ADC chip MSC1210, and also to discuss how to take advantage of MSC1210 and realize it by software. A D/A converting circuit with high performance using the DAC1220 was established at the same time.(3) Data processing system base on DSP. The paper presented the hardware of data processing system, introduced several practical algorithms of digit filter and then narrated how to design and realize FIR filter in details.(4) Demarcation of the system's performance index. The paper calibrated and demarcated the performance index with voltage reference and 6 12 digital millimeter, pointed out the cause of errors by processing the experiment data and analysis, and then brought forward the better devise.Compared with foreign countries, the research on high precision process calibrator comes out later and has a relatively low level in our country. However, its application is becoming more and more widely today. The calibrator designed in the paper reaches a high standard in measurement and it is also close to the foreign production with respect to output accuracy. The production can promote the research on high accuracy process calibrator inland.